Such a sewing machine is the subject of U.S. Pat. Application No. Ser. 458,701 corresponding to German application P 37,24,786.7-26. It contains a device for automatically adjusting the height position of the upper feed system to the actual working height of the material to be sewn. One possible embodiment of the control device used here is a hydraulic three-position control device. To achieve an idle stroke, this control device has a pre-tensioned spring system arranged between the adjusting piston of the control device and the presser foot as well as the upper feed foot, which spring system produces the range of insensitivity necessary for the three-position control in cooperation with a hydraulic device.
This measure is expensive. The design, which consists of both mechanical and hydraulic components, has a plurality of moving parts which require space and whose hydraulic sealing is expensive.